On April 19, 1999, about 1030 central daylight time, an experimental Durrwachter Wittman Tailwind W-10, N1194K, registered to a private individual, operating as a Title 14 CFR Part 91 personal flight, crashed on takeoff climb from a private grass airstrip about 5 miles east of Dover, Tennessee. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage and the commercially-rated pilot and a passenger received serious injuries. The flight originated from the airport about 5 minutes before the accident. According to an eyewitness, one of the pilot's sons who was videotaping the flight, he heard a "popping" sound and it appeared as if the airplane lost power and crashed in a pasture. He stated that he ran over to the crash and disabled the electric fuel pump that was gushing fuel from a broken fitting. He stated the aircraft was actually based at Humphrey's County Airport, Waverly, Tennessee, and his father was demonstrating the newly completed airplane to his sons. Another eyewitness stated the aircraft was about 200 feet agl, in a takeoff climb when it appeared to lose power and commence a descending left turn. He said he thought the pilot had a problem and was trying to make it back to the runway and didn't quite make it. He made his way over to the crash site and extricated the two occupants. He stated there was a strong fuel smell and he could hear something continue to operate. According to FAA inspectors, postcrash examination of the aircraft and accident site revealed the site smelled heavily of automotive fuel, and the airplane's fuel filter contained uncontaminated fuel. Flight control path continuity in all axes appeared intact and functional. The engine was a Subaru automotive 2.2 liter displacement, 4-cylinder inline configuration utilizing liquid cooling, electronic ignition and electronic fuel injection. Subsequent engine removal and remounting to a specially made engine stand by an FAA inspector/ Subaru automotive technician produced an immediate start and smooth operation for six successive starts and shutdowns. Because the airplane installation used a specially designed radiator that was destroyed in the crash, the test runs were conducted without liquid cooling and were time limited. To simulate conductive and advection heating of all peripheral components by the core engine as would occur in airborne operation, a heat gun was used on the components, and especially the electronic modules, to heat their integrated circuits to high operating temperatures. The engine was run to near maximum power with no abnormalities noted. Because the boost pump, ignition, and fuel injection systems were electronically controlled and powered, all circuits were tested for security of connections and specified volts and amperes. The alternator output was checked and produced a steady 12 volts.